Should HTHS be redefined as "operating viscosity" ?

[Shannow]

or somesuch.

Can have a thick oil with a low HTHS, or a thin oil with a relatively high HTHS.

Which means the most WRT engine wear ?

(and economy)

 

[bigpaulo]

Ever consider that the reason why some engines return much better UOA wear results than others is because their "operating temperatures" are lower than either HTHS (150 C) or other engine operating temperatures (which may be even higher)?

Given variability of engine designs, as long as HTHS is close to an average for operating temperatures, then I'd argue there's no reason to change its definition.

 

[Dr. T]

I can see where the thought of a viscosity score at 150C can be construed as a 'measuring viscosity'.

However, every engine has a different operating temperature range and it's different depending on outisde ambient temperature. Therefore different viscosities are occuring in the engine at all times. Certainly discounting both the "it's too thick" and "tighter engine tolerances" thereories with respect to viscosity use.